L1的实际功率不是额定功率L1的电阻R1=6^2 /6 =6欧姆L2的电阻R2=12^2 /6 =24欧姆电流I=12/(6+12)=0.4AL1的实际功率=I^2 *R1=0.4^2 *6=0.96W
